DC Motors and Servos using Arduino

Help & Support Robot Parts
1

Dear Sir or Madam,

I have been teaching Grade 7 students about the basics of Arduino for about 8 years. We ordinarily get as far as using pushbuttons and light sensors. I would like to go further and show them how to create a device, such as a small car, driven by a DC motor. We may go as far as to steer the car using a servo. I am writing about the which type of the following I would require for these types of projects, and your suggestion for the appropriate Robotshop products.

  1. Capacitors: my understanding from checking at Arduino and other sites is that a 470 microF capacitor is suitable for a servo. If I wanted a set of 10 for my class, which robotshop product would be best suited?

  2. Diodes: Again, from what I have read, a 1N4001 diode is suitable for protecting a microcontroller from charges from a DC motor. Is this correct? If so, which robotshop product would be best to have a set of 10?

  3. Transistors: From my reading, it seems that NPN TIP120 is a helpful transistor for controlling a DC motor or servo (the servo in my hand is a Futaba S3004). Once again, can you give me advice as to which robotshop product would be best to make a set of 10 for my class?

If you can give me better advice about the products I will need, I would be pleased to have it. My understanding is that our DC motors are 1.5 V. They are sufficient to drive a small vehicle which is powered by a solar panel. I have in mind that our Arduino-controlled vehicle will be run by a 9 Volt battery. Will the motor and the arduino require separate batteries? Diagrams I see online often show the motor powered by a battery, but nothing powering the microcontroller. Thank you for your help.

Best wishes,

David

2

Hi David,

First, you might want to check this Smart Car 2.0 Kit for Arduino we offer that might interest you. You can take a look at the User Manual through this link to have a better idea about this kit.
Also here is a link to the Arduino Kits we offer.

]This Aluminum Electrolytic Capacitor Pack has 10 x 470uF capacitor./:m]
]Yes, the Diode will provide a safe path for the inductive kickback/BEMF (Back Electromotive Force) and thus, protect the MCU/Arduino. We unfortunately don’t offer the 1N4001 diode separately. The SparkFun Beginner Parts Kit includes 5 x 1N4001 and the CK-1000 Basic Electronic Parts Kit includes 2 x 1N4001 among with other electronic components/:m]
]Again, we don’t offer the TIP120 transistor separately but it’s included in this Components Pack. There are many circuit diagrams using the TIP120 NPN transistor because it is a darlington transistor. Its maximum voltage of 60V and the max current of 5A let you control a variety of external high current devices with low voltage circuitry because of the darlington arrangement. You can probably go with this Transistor Pack and use the included BC517 NPN Darlington Transistor that can handle a maximum of 1.2A./:m]
It’s always a good practice to separate the controller and the motor power supply. You can use this DFRobot 7.4V Lipo 2500mAh Battery (Arduino Power Jack) for example to power the Arduino (w 7.4V Lipo Battery Charger).